The usual indignation greeted David Blunkett's latest assault on the civil liberties of the young. But he is right. What is he to do about crime falling by 25%, police numbers higher than ever, yet fear of crime as bad as ever?

Few believe the good crime figures: they still fear out-of-control people roaming the streets, with graffiti and vandalism as constant reminders of social disorder. With 60,000 official reports of vandalism and threats in one sample day - the unreported number presumably far higher - crime figures just don't capture the way people feel. After all, it only takes a little criminal behaviour and a few bad neighbours to destroy the sense of security for thousands of people around them. This latest push to give communities the nerve to challenge trouble-makers comes with a determination to change the social climate, no less.

Not much bad behaviour happens in the Acacia Avenues where opinion-formers live. This is not about middle-class streets with prominent burglar alarms. David Blunkett is often accused of pandering to Daily Mail prejudices, but this policy is less about the well-heeled resenting beggars under cash machines than the quality of life of people too poor to own bank cards. It is about the worst estates in the highest crime zones. New campaigns include name and shame leaflets featuring photos of all the local youths banned from the area by anti-social behaviour orders (asbos). Fixed penalty notices, parenting orders and behaviour contracts will be used more forcefully. With such symbolic gestures the home secretary seeks a transforming "culture change".

Sceptics shrug and dismiss this as political posturing, not practical policy. They point out how few asbos have actually been used, costing £5,000 each and taking three months to process - hardly a return to the days of the local bobby delivering a clip round the ear. The liberal left tends to think the only way to change social climates is by long slow interventions over many years. But this defeatism fits badly with the left's general view that governments can make radical change for the general good.

Consider how the same criticism was made against the authoritarian tone of the New Deal for the young unemployed, because of its emphasis on compulsion. But its use of both carrot and stick was the key to its success. The young had to participate - but they got good personal advisers with education, training and employment options of better quality than before. It worked - not just in the actual numbers of people directly finding jobs, but in a more visceral, climate-changing way. The message went out loud and clear that work was expected and hopelessness was not an option: 75% of the long term unemployed found jobs. Cultures can be changed - there are growing numbers of schools that prove it - but it usually takes sticks as well as carrots.

The trouble is that sticks are cheap and there is a carrot shortage. Ministers boast about schemes that, in reality, barely exist in most places. Talk to housing officers about what they need to build orderly communities and they say yes, asbos are useful. But right at the start, when families first cause trouble, they need good social workers to come quick and often, good mental health workers, professional mediators, youth workers and places for young people to go - an array of services before a crisis looms. Councils are obliged to rehouse the vulnerable homeless or mentally ill, but find they rapidly cause trouble and lose their tenancies again for lack of support or sheltered housing. Over-stretched services are never there for early prevention.

Take the recent high-profile blitz on street crime which successfully reduced muggings. The report on it by the chief constables found that the arrested criminals were all given an assessment for drug treatment within the target 24 hours. But they also found that the waiting list to get them into treatment was three months, so 95% never turned up. Targets often hide a less rosy reality. When the government promises 200,000 "drug treatment places" by 2007, some people are still waiting for a year and few residential places are planned, which is what addicts need most.

Or take mediation, often quoted by ministers as a way of reconciling neighbours and modifying bad behaviour. Mediation UK reports that its Cardiff scheme has closed for lack of funds, there is no scheme now in Glasgow and elsewhere. Yet early mediation can reconcile young and old neighbours at low cost, avoiding the courts and leaving an 80% satisfaction rate. Recently kids on scooters raising hell on a north London estate were brought together by mediators with residents: a piece of waste land was found for them.

Everyone knows what works in crime prevention. In a recent poll by Rethinking Crime and Punishment, people asked what would best reduce crime ranked "better parenting" top, followed by more police, better schools and constructive activities for the young - more punishment rated only seventh on their list. Everyone knows what works and it begins with parents. But as everyone says, there are still few services to catch children very young and to shore up chaotic families. The magic mix is strong consistent support on every front, backed by sanctions. Parents who need it most are least likely to attend parenting classes - but when forced, the results are good, and so is their own satisfaction.

Earlier this year, 13-year-old "terror triplets" in Gillingham were named and shamed across the press for breaking an asbo imposed for causing trouble. But their asbo had utterly failed to trigger the massive intervention that the family needed. What emerged when they were in court for breaking it was a chaotic family with five children and never-employed parents who had moved so many times the children never settled into school. There was no "multi-agency plan" for this family, despite the alert that should have sounded. Labour is discovering just how deep the need is, how expensive the real solutions are and how few quick fixes there are. Asbos are a necessary sanction - but without intensive family help they can't alone turn the tide of social mayhem.

The money announced yesterday was embarrassingly small: £22m buys little. With no new money in the pot, David Blunkett should demand that communities be allowed to keep the fines they collect to finance better local youth projects. The chancellor might in turn suggest that the home secretary seek savings from his out-of-control prison population - 74,000 and rising at £30,000 a year each. If he could summon the same political courage as Douglas Hurd, who let out minor criminals in great numbers, each prisoner released would yield the cash to prevent many younger ones following in his footsteps. Everyone knows what works, and it is expensive - but nothing is as costly as prison.